class Faker::Travel::TrainStation

def fill_missing_inputs_with_samples(region, type)
  regions = %w[germany spain united_kingdom united_states]
  types = %w[metro railway]
  if region.nil? && type.nil?
    region = sample(regions)
    type = sample(types)
  elsif region.nil?
    validate_arguments(type, types, 'type')
    region = sample(regions)
  elsif type.nil?
    validate_arguments(region, regions, 'region')
    type = sample(types)
  end
  [region, type]
end